Author: Roberto Doati

(1981-82) sound synthesis [8’ 06″]

Premiered at International Computer Music Conference, Palazzo del Cinema, Venezia, September 27th 1982

This work utilizes a timbre space built on three dimensions:

1. spectral energy distribution;
2. spectral fluctuation;
3. (coinciding with I.) high frequency energy which precedes the full attack of the tone.

The sound synthesis models used are simple waveshaping and FM; this one just for the third dimension (it adds the high-frequency energy needed).

The macrostructure of the composition is generated by the projection, on a two-dimensional space with frequency as the ordinate and time as the abscisa, of an architectural structure plan. By means of the ‘slowing perspective’ technique I achieved the desired temporal extension. As regards the choice and the treatment of the macrostructure and its internal organization, they depend exclusively on my compositional parameters: symmetry, regularity, direction, velocity, focus and flight point (terms borrowed fron the visual arts world). The internal temporal organization of the polyphonic rhythmic structures that make up the macrostructure is given by the position of the focus. This one is determined too by the parameters above mentioned.

Each structure takes the timbre that occupies the corresponding position in the timbre space.

The composition has been realized with the facilities of the Centro di Sonologia Computazionale, University of Padova.

(1980-81) sound synthesis [LP Edipan PAN PRC S20-16] [6’ 54″]

Premiered at Varadero Music Festival, Cuba, April 19^th 1981

The macrostructure is made up by seven different curves which correspond to the graphic representation, on a two-dimensional space with frequency as the ordinate and time as the abscissa, of the variations of as many circumference arcs.

This macrostructures determines the formal parameters (repetition series, action time, duration, number of voices, movement in the time-frequency space) of seven kinds of polyphonic rhythmic structures; these are graphically generated on the score mentioned above not with the intention to reach a musical parallel of them, but because previous experiences have shown that the formal perception of both visual shapes and acoustic events are ‘controlled’ by the same laws. Here I have utilized the descriptive principles which have been formulated by the Gestalt School: proximity, similarity, good continuation, etc. The law of Pragnanz, for example, favours the choice of simple, regular, symmetric shapes, and such are the structures here employed. The pure sounds that form them (sine waves with frequency jitter) lose their identity for make up the whole.

These principles being more effective when they are combined with symmetry, I have placed on the left channel the same structures of the right one in specular form.

The composition has been realized with the facilities of the Centro di Sonologia Computazionale, University of Padova.